Immersion lamp for a photochemical reactor and its use

ABSTRACT

An immersion lamp for a photochemical reactor with a discharge tube fitted in an outer bulb through which an inert gas flows having a lamp bulb with axially opposite mechanically stable electric terminals is held and contacted in a holder in the outer bulb, and the outer bulb is tubular and has at least one open end projecting into a hollow space in a connector head to provide electric contact and a secure mechanical support; the open end of the outer bulb is surrounded by at least one elastic seal which is surrounded axially by two inelastic metal plates laid on it having cut-outs for the passage of the end of the outer bulb and screws; the pressure exerted by said screws deforms the elastic seal radially to such an extent that it seals against both the outer wall at the end of the outer bulb and the inner wall of the hollow space and secures the outer bulb centrally in the connection head.

FIELD OF THE INVENTION

The invention relates to an immersion lamp for a photochemical reactorwith a discharge lamp, wherein the discharge lamp is seated in anexterior bulb through which an inert gas flows and has a lamp bulb withaxially oppositely located, mechanically stable electrical connectors,which is held in and connected with a socket of the exterior bulb,wherein the exterior bulb is tube-shaped and has at least one open endand projects into a chamber of a connecting head for electricalconnection and secure mechanical support, and its use.

BACKGROUND OF THE INVENTION

An immersion lamp in accordance with the structural system containing anHg high-pressure radiator is recited on page 13 of the prospectusHeraeus Original Hanau D 310625/2C 9.89/VN PK of W. C. Heraeus GmbH. Ascan be seen in FIG. 8, the radiator is fastened in the immersion tube bymeans of straps and seals via a radiator support with a lead, whereinthe immersion tube in turn is located in a cooling tube with straps andseals. In this case the immersion tube is flooded with an inert gas viaan inlet connector and an outlet connector at the head plate. Thecooling tube offers the opportunity of water cooling between theimmersion tube and the reaction material. The connection between thehead plate or immersion lamp head, as well as the connection of theimmersion tube, with the cooling tube takes place via normal flangeconnections.

An immersion lamp with a mercury high pressure radiator is furthermoreknown from DE-PS 855 397, which is housed in the interior of an outerbulb closed at one end and wherein the area intended for the radiationto exit consists of transparent quartz glass and its remaining areas ofopaque quartz glass. The exterior bulb is sealingly fixed in an openingof the wall of the radiation vessel by means of a circumferentialpacking box seal; the exterior bulb is closed off by means of abox-shaped connecting head with a current allocation and a cooling airconnection, wherein the connecting head is fastened by means of strapsat the upper end of the exterior bulb.

Assembly in case of changing the exterior bulb or the discharge lamp hasbeen shown to entail problems because in this case it is necessary tohandle straps and seals especially carefully to assure sufficientstability and sealing.

Furthermore, U.S. Pat. No. 3,617,701 describes an electrical heatingelement which is surrounded by a quartz glass tube closed off on oneside to form an immersion tube and is sealingly maintained with its openend in a connecting head by means of an epoxy resin adhesive.

Here, too, assembly or exchange of the quartz glass tube entail problemsbecause of the adhesion, since great skilled efforts are required toachieve sufficient stability and sealing.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a mechanically rigid,sealing and clamping mounting on an open end of an outer bulb of animmersion lamp, wherein the mounting is intended to make simple assemblypossible, in particular in the course of changing the exterior bulb orexchanging the discharge lamp.

This object is attained by the present invention.

Preferred embodiments of the invention as well as its use are recited inthe dependent claims.

It has been shown to be advantageous that the seal consists ofmodule-like elements so that it is possible, depending on the length ofthe radiator or the flow pressure acting on the exterior bulb, toachieve an optimal adaptation with sufficient stability by means ofindividual or several module-like sealing elements. A further advantageis to be considered that a quick change of the exterior bulb or thedischarge lamp can be performed by doing away with the setting times ofadhesives.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject of the invention will be explained in detail by means ofFIGS. 1, 2 and 3.

FIG. 1 is an elevational, broken-sectional view which shows an immersionlamp with an inserted radiator lamp in longitudinal section.

FIG. 2 is an elevational, broken-sectional view which shows alongitudinal section of the immersion lamp turned by 90°, with respectof FIG. 1.

FIG. 3 shows a top plan view of the sealing body.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with FIG. 1, the immersion lamp has an exterior bulb 1, inwhose interior the discharge lamp 2 is located and is electrically andmechanically connected with the contact device in the connecting head 7via the contacts 3 and 4, as well as the associated guide and contactrods 5 and 6. The open end 8 of the exterior bulb 1, closed off at oneend, projects into a hollow chamber 9 of the connecting head 7 which, inthe shape of a hollow cylinder, is provided with a greater interiordiameter than the exterior diameter of the also cylindrically formedopen end 8 of the exterior bulb 1. Two sealing bodies 10 and 11 areplaced coaxially with the axis 12 of the exterior bulb 1 between theinterior wall of the hollow chamber 9 and the upper end 8 wherein,viewed in the axial direction, the sealing bodies 10 and 11 are eachsurrounded by ring-shaped inelastic plates 13, wherein these plates areprovided with openings for passing through the exterior bulb andthreaded bolts, as shown below in FIG. 3. The threaded bolts areinserted along the schematically represented dashed lines 14 and 15 andsubsequently fastened by means of a nut placed thereon or by screwingthem into the lower flange 16 of the connecting head 7 in such a waythat the sealing bodies 10 and 11 are deformed because of the pressureexerted along the axis 12, i.e. in the radial direction, so that theysealingly rest on the interior wall of the hollow chamber 9, as well ason the exterior wall of the open end 8 of the exterior bulb 1, andsimultaneously form a secure mounting or centering of the exterior bulbbecause of their resilience. It is assured in this way that even acomparatively long exterior bulb is stably maintained in its centeredposition under the pressure of flow of the medium surrounding it.

As can be seen by means of FIG. 1, the ring-shaped plates 13 areadjusted in the flange 16, preferably by a thread 17, in such a way thatthe ring-shaped inelastic plates 13 are always maintained at a distancefrom the interior wall of the hollow chamber 9, as well as the upper end8 of the connecting bulb 1, while the sealing bodies 10 and 11, whichextend inward and outward in the radial direction, touch the upper end8, as well as the interior wall of the hollow chamber 9 sealingly andwith sufficient mechanical stability. The threaded bolts 19, only shownschematically in FIG. 1, are inserted from above through the openings14, 15 prior to the placement of the head plate 18 of the connectinghead 7 and screwed together with the flange 16 by means of the threads17. A comparatively simple change of the exterior bulb 1 or thedischarge lamp 2 is possible in this way, since it is necessary toremove only the head plate 18 from the connecting head 7 for disassemblyand to loosen the screws along the represented lines 15 and 15sufficiently so that the compressive force on the sealing bodies isremoved, in the course of which the upper end 8 of the exterior bulb 1can be removed in a simple way in respect to the connecting head 7 andcan be pulled out toward the top, for example.

FIG. 2 shows a longitudinal section, turned by 90°, of the immersionlamp illustrated by means of FIG. 1, wherein the same reference numeralsas FIG. 1 have been kept to the extent possible, so that a detailedexplanation is not necessary FIG. 2 shows the insertion of the threadedbolt along a schematically represented line for improved clarity,wherein the thread 21 of the threaded bolt 19 is screwed into a blindbore-like thread 17. The employment of a blind bore-like thread isnecessary for obtaining the sealing of the flange 16 of the connectinghead 7 against the fluid located under it.

As will be explained below by means of FIG. 3, the open end 8 of theexterior bulb 1 is surrounded by a plurality of such threaded bolts 19,which also is true for the connection long the lines 14 and 15 in FIG.1.

FIG. 3 shows a top view along a section A-B of FIG. 2 of the sealingelement consisting of ring-shaped plates 13 and sealing bodies 10 and11.

The ring-shaped inelastic plate 13 resting on the upper sealing body 11can be seen in the top view of FIG. 3, which also has the openings 14,15 leading through the sealing body along the lines 20 and 23, of whichthe heads of the bolts 19 projecting above the respective opening arevisible. The sealing body 11, which extends by means of pressure sealingin the radial direction, can be seen underneath the ring-shapedinelastic plate 13 and rests resiliently sealing against the upper end 8of the exterior bulb 1 represented in section, and rests in the radialexterior direction against the interior wall of the hollow chamber 9,wherein the wall surrounding the hollow chamber is identified by thereference numeral 24.

In the compressed state of the sealing body(ies), the interior diameterof the inelastic plates is always larger than that of the sealingbodies, while the exterior diameter of the plates in the compressedstate is always less. The ratio of the thickness of the inelastic platesto the thickness of the sealing bodies is in the range of 1:2 to 1:10,preferably in the range of 1:3.5.

VA steel has particularly proven itself as a material for the inelasticplates, while the sealing bodies preferably consist of an acid-free,UV-resistant resilient material, such as Viton.

We claim:
 1. An immersion lamp for a photochemical reactor comprising:adischarge lamp (2) connected to a connecting head (7) formed with ahollow chamber (9), the discharge lamp (2) being seated in an exteriorbulb (1), an inert gas being disposed within the exterior bulb (1); thedischarge lamp (2) having axially oppositely located, mechanicallystable electrical connectors 5, 6 held in and connected with a socket ofthe exterior bulb and extending into said hollow chamber (9), theexterior bulb (1) being tube-shaped and having at least one open end (8)which projects into the hollow chamber (9) of the connecting head (7),wherein the at least one open end (8) of the exterior bulb (1) issurrounded by at least one resilient sealing member (10, 11) which, whenviewed in the axial direction, is enclosed by two inelastic plates (13)placed thereupon in the form of a sandwich, the two inelastic plates(13) have openings which accommodate threaded bolts (19) having threadedends which pass therethrough; the connecting head (7) at a lower endthereof has a flange (16) with a passage for the at least one open end(8) of the exterior bulb (1), the flange (16) being provided with blindbore openings (17) with internal threads for receiving the threaded endsof the threaded bolts (19), the blind bare openings (17) being disposedon a side of the flange (16) facing away from the discharge lamp (2),wherein the at least one resilient sealing member (10, 11) is deformedby compression by the threaded bolts (19) in the radial direction suchthat the at least one the resilient sealing member (10, 11) restssealingly against an exterior wall of the at least one open end (8) ofthe exterior bulb (1), as well as against an interior wall of the hollowchamber (9) to fix the exterior bulb (1) substantially in the center ofthe connecting head (7).
 2. The immersion lamp in accordance with claim1, wherein one of said two inelastic plates (13) is disposed between atleast two of said at least one resilient sealing members (10, 11) andsaid at least two of said at least one sealing member (10, 11) areaxially disposed in respect to each other along a lonqitudinal axis ofthe exterior bulb (1).
 3. The immersion lamp in accordance with claim 2,wherein the interior wall of the hollow space (9) is formed as a hollowcylinder in an area of the connecting head (7) wherein the at least oneresilient sealing member (10, 11) and the two inelastic plates (13) aredisposed.
 4. The immersion lamp in accordance with claim 3, wherein theexterior bulb (1) consists of a tube closed off at one end.
 5. Theimmersion lamp in accordance with claim 3, wherein each opposite end ofthe exterior bulb (1) is an open end which is connected to, centeredtherein and sealed by the connecting head (7).
 6. The immersion lamp inaccordance with claim 1, wherein the interior wall of the hollow space(9) is formed as a hollow cylinder in an area of the connecting head (7)wherein the at least one resilient sealing member (10, 11) and the twoinelastic plates (13) are disposed.
 7. The immersion lamp in accordancewith claim 1, the exterior bulb (1) consists of a tube closed off at oneend.
 8. The immersion lamp in accordance with claim 1, wherein eachopposite end of the exterior bulb (1) is an open end which is connectedto, centered therein and sealed by the connecting head (7).
 9. Theimmersion lamp in accordance with claim 1, wherein a ratio of thethickness of each of the two inelastic plates (13) to the thickness ofthe at least one resilient sealing member (10, 11) is 1:2 to 1:10. 10.The immersion lamp in accordance with claim 9, wherein the ratio is1:3.5.
 11. The immersion lamp in accordance with claim 1, wherein thetwo inelastic plates (13) are made from steel.
 12. The immersion lamp inaccordance with claim 11, wherein the at least one resilient sealingmember (10, 11) is made of an acid-free, UV-resistant material.
 13. Theimmersion lamp in accordance with claim 12, wherein a ratio of thethickness of each of the two inelastic plates (13) to the thickness ofthe at least one resilient sealing member (10, 11) is 1:2 to 1:10. 14.The immersion lamp in accordance with claim 13, wherein the ratio is1:3.5.
 15. The immersion lamp in accordance with claim 1, wherein the atleast one sealing member is made of an acid-free, UV-resistant material.